Self-inflating balloon type formation tester



April 24, 1956 A, B. HILDEBRANDT 2,742,968

SELF-INFLATING B11110011 TYPE FORMATION TESTER F11ed Dec. 11, 1952 1alexander' n-fildebfmdt, Saver-150i' 2,742,968 `retreatedApr. 24, 1956`United States Patent Office SELF-INFLATING BALLOON TYPE FORMATION TESTERAlexander B. Hildebrandt, Tulsa, Okla., assignor to Esso Research andEngineering Company, a corporation of Delaware This invention isconcerned with an improved apparatus for securing samples of formationfluids from a well bore to determine whether oil bearing strata have`been encountered. More particularly the invention relates to animproved formation tester of the inflatable balloon packer type that maybe attached to the lower end of a drill pipe, wherein novel means areprovided for inilating and detlating the balloon packer.

In conventional oil well drilling operations fluids known as drillingmuds are employed to aid in carrying away cuttings and also to maintaina hydrostatic-head in the well to prevent the uncontrolled escape ofgases or liquids from various formations encountered during drilling.One disadvantage of drilling with a drilling mud is that the sampling ofnatural fluids occurring in various formations is thereby rendereddiillcult. To overcome this disadvantage various types of formationtesters have been devised which are provided with means for reducing thehydrostatic pressure in the vicinity `of the formation to be tested inorder that a sample of the natural fluids can be taken.

Many of these formation testers are provided with i.

inflatable elastic sleeves or packers for sealing off the portion of thewell in which it is desired to reduce the hydrostatic pressure. The useof such elastic packers is particularly desirable since they can beexpanded to give a thorough seal and yet may be readily removed fromthe` well after being deflated. Furthermore it is possible to positionthe elastic packers at any desired point in the well with very littlediiliculty.

In formation testing using an inflatable elastic packer run on drillpipe or tubing some means must be provided for inllating the packer. Theconventional means for doing this involves pumping drilling mud or otheriluid such as plain water downthe pipe, so that with a` suitablearrangement of valves the necessary inflation pressure can be applied tothe inside of the packer. Suitable means are provided to hold thepressure in the packer until the test has been completed. After thepacker has been set against the formation the usual procedure is toreduce the pressure inside the drill pipe until` formation iluids canflow through it to the surface. j This can be done merely bysubstituting plain water for drilling mud in thelpipe but in many cases`it is necessary to swab down the iluid level in the pipe to the desiredextent. An alternative procedure is to place a previously evacu-V atedsample chamber in the drill pipe and produce fluids into this samplechamber. With such a procedure the amount of iluid that can be sampledis limited by the capacity of the sample chamber. Obviously a procedurewherein the drill pipe can be run in empty is preferable since itprovides for considerableytest capacity without the necessity ofswabbing outthe pipe.` i i lt is an object of the present invention toprovide means for formation testing in which an inflatable packer isused but in which neither an evacuated sample -chamber nor a swabbingoperation is necessary. Itis a further object to provide a formationtesting device that may be run into` the bore hole on an empty drillpipe and the packer inflated without requiring thatA fluids be pumpeddown the drill pipe, thus keeping the pipe empty for the collection of asample of formation fluids.

Briefly the invention consists of an apparatus provided with meanswhereby the hydrostatic mud pressurev in the bore hole at the level ofthe formation under test is utilized to inflate the packer and toautomatically collect a sample of the formation tluids as soon as thepacker has set against the selected formation.

The nature of the invention and the objects thereby accomplished will bemore fully understood from the ensuing description and from theaccompanying drawing in which:

Figure 1 is a vertical sectional view of the upper portion vof arepresentative embodiment of the invention in position in a bore holeand j Figure 2 is a lower continuation of Figure l.

Referring specifically to the drawing it will be seen that the formationtester depicted is provided with a support member 12 that is attachableto a tool joint 11 which in turn can be attached to the lower end of asectionof drill pipe (not shown). `The apparatus is shown in position`in a bore hole 10. The support 12 terminates in a lower rounded noseportion 13 to facilitate lowering through the b'ore hole. Positionedwithin the support member 12 is a cylindrical tube 16 which delines withthe bore of the support member an annular passageway 17,`whose functionwill be explained later. There is no communication between passageway 17and the bore 4 2 of tube 16 Adjacent` its upper end, lsupport member 12is of enlarged external diameter to provide a shoulder 14 and somedistance belowthis shoulder the support member has an `annularprojection 1S in which an external groove is provided to receive aringseal 18. Fitting slidablyover the exterior of support member 12 is asleeve member 19 having adjacent each end an internal groove, each oneof which receives a ring seal 21 or 22. The middle portion of the boreof sleeve 19 is of enlarged diameter so that it fits slidably againstprojection 15 and defines with the adjacent portions of support member12 an annular chamber 24 above kthe projection 15 and an annular chamber`26 below projection 15. A spring 27 is positioned within annular space26 and presses at its upper end against the lower shoulder of projection`15 and at its lower end against the lower shoulder provided by theenlargement of the bore of sleeve 19. A port. 25 in the wall of sleeve19 provides exterior iluid access to chamber 24. `A plug 53 set intosuitably aligned openings in support member 12 and tube 16 has a centralbore that provides a channel 54 connecting chamber 26 with bore 42 oftube 16. V

At the upper end of sleeve 19 an exterior shoulder 28 is provided whichsupports the lower end of an annular mechanical packer 29 that surroundssupport member 12. The upper end of packer 29 lits against downwardlyfacing shoulder 14 on support member 1l2. The packer 29 is attached atits upper end to the support member 12 and at its lower end to thesleeve 19 and is held in place at each end by suitable means, as forexample, by the tightly wound wires 3i). Thus as sleeve 19 movesupwardly with respect to support member 12 packer 29 will be made toexpand against the walls of the bore hole as represented by the dottedlines 29a; Preferably the expansion of the packer is aided by a body offluid 31 retained with the annular space defined by the packer and thesupport member 12.

Fastened `to the exterior of the lower portion of support member 12 isan inflatable elastic packer 33 held in place at each end by suitablemeans such as tightly wound wire 34. Fluid commmunication between theannular .passageway -'17 `andthe ination chamber 35 defined by packer.33V and the support member- -12 is testablished through port 36.

An external recess 33 is provided in the wall of theinat'ablepackerfandicommunicating Y'with this vrecess is `-a productiontube 39 iin-wh`ich-are `positioned yinterconnected `packing -elenientsti-in Ctheunranner disclosed in U. S. Paten't2j60l),f173 lof'fBenAW.'Sewell and'George Ramsey. "These A.packing elements establish ano'nc'ollap`sible passageway for t'the entrance of 'productionl iluidsas -fully'discussed -in 4the `aforementionedpatent. Cornmu'nication`between the Aproduction ltube' 39'fand Athe in'ner bore 21210i tubev16'-is V'established 'through "channel 41 in an enlarged portionf'ofwhich'is positioneda check v'alve'i, which4 issetto-open'at'a'low'pressure differential, say 2ior3 pounds. YA channel-4`5irl-thehead'p'ortion r13 of fthe support' member lconnects annulus: 174with an ex ternal port 50 through a check valve 46. Th'eifuuction ofethis-channel 'and'c'heck valve will'be explained later.

When the'apparatu's is preparedfor lowering into a bore hole the packers29 and `33`are 'both"in'th'e'v nonexpanded'position and a"frang'ib'le orrupturable 'seal 56 'is positioned -in'thetop of'tube 16to Vsealdfl'inner borev 42 fromthe enlargedy bore 5S which is 'in open communicationwith the open 'drill pipe above. When Ithe desired 'level hasb'eenreached in the bore 'hole a godevil-58y or similardeviceis droppeddown through the drill-pipe to break the seal 56. lTo prevent 'thego-devil from Vsealing off tl-iejpassagewayit maybe desirable to providethe go-devilwithribs 59. l

When the seal 56 `isy broken the inner 'bore`42 will be exposed toatmospheric pressure, i. e. the pressure with inthe open'dr'ill pipe.4Since the pressure of the drilling mud present A-i'n vthe borehole atthe depth of the apparatus 'is higher 4than atmospheric, sleeve 19 willslide upwardly"with respect 't'of support member 12.

When the pressure within" bore 42 'is essentially the same as thepressure in the bore hole annulus, which will be' the casebefore seal'56is broken, the force against the inner 'shoulder of Asleeve 19 thatdelines the top of chamber`24 will be count'e'rb'alanced by the forceagainst the inner shoulder of sleeve 19 'that defines the bottom ofchamber 26. 'When the pressure within 'chamber 26 is reduced, however,as a 'result of breaking seal 56, the upward Vforce 'on the sleeve willbe. greater than the downward force. VHence sleeve 19 will move upwardagainst the slight bias exerted by spring 27 and Ipacker 429 will beexpanded outwardly to :the ,position .indicated by the dotted' lines29a. vrThus ,the packer 29 willl be .expanded to seal oft' vthe borehole annulus below this ypacker from the bore hole annulus above thepacker.

"Spring 27 is not essential to the above described operation of sleeve19 but it is xpreferred that it be used so that when the pressure Vinthe borehole annulus is only slightly higher than .thepressure in bore42, ywhich could occur as the apparatus' isv being lowered yinto thebore hole, the packer will not set prematurely. Thus aspring is selectedsuch lthat sleeve .19 will not zmove up until thev pressurek dilerence`exceeds say' -50 pounds. The vpurpose lof ring seals 18,21 and22 istcgprevent uid leakage past the 'sliding parts that they contact. y l

v4Because of the reduction in pressure within -the bore 42 uponruptureof the seal 5 6, drilling mud-will also begin .to enterproduction tube 39 past valve-43 and -into the inner bore 42. vAs thevolume of `rnudfin the`bore holeannulus in the vicinityof-the packer`33is thus reduced drillingmud will enter through wport -51 .into annulus17 V.and flow out through vport 36fintoithe inflation.,chamber 35 withinpacker33. This mud 4ilow will continue .as additional 'fluid entersproductiontube 39 until the packer-33 presses up A againstthewalls ofthe bore hole. `Fluid within formation 60 will lthenilow throughIthejproduction tube39 into they innerbore 42.

The purpose of vcheck valve 46 is "to controlth'e inating pressurewithin the packer 33. Thus for example --ifthc'uidvpressure inthebore'hole annulus above-packer 29 should exceed the fluid pressure inthe bore hole annulus at the bottom of the tester by more than say 50lbs. fluid will ow down annulus 17 through the check valve 46 until thepressure differential drops below 50 lbs. It should be noted that packer33 does not have to support more Vthana smalliditferential pressureand-hence its principal function is to isolate the portion of formation60 being tested. l

When it is desired to terminate the test, drillingmud or otherIluidrn'ay be pumped down the drill pipe until the pressure within theinner bore 42 is about equal to the pressure in the bore hole annulus inthe Vicinity of sleeve 19. When the pressure within annular space 26approaches the pressure in the bore hole annulus sleeve 19 will movedownward and retract packer 29. As a result, the bore hole pressuresabove and below packer 2'95w`ill bec'omeequalized 4and packer 33 willbecome d'atedfsnce jthe'gpressures inside and outside the packer 33"willalso'jbecome equalized and the elasticity of lthe p'acker"materialYwlllfdraw 'the packer inwardly, 'the "in- Hating llluidminannular space35 escaping through port 316,1;annulus`17fand port S1. The fluid samplethat has been 'collected within vthe bore 32 will be prevented fromescaping by the'check valve 43.

In La 'modification of 'the invention packer 29 may be omitted, andinstead a conventional mechanical packer substituted; Such a packerwould be mounted on support members movable relative to each other, theUpper one 'attaching' to lthe drill pipe andthe lower one to support 12.A conduit within the support members would connect annulus 17 with anexterior port above the rnechanical kpacker in the same manner as port51. A conventional ta'ilpipe rwould be attached tothe bottom of support12 'and 'would rea'ch to the bottom of the borehole Vso thatthemechanical packer could be set by placing weight 'on the'dr'ill pipe, asin conventional practice. The inationlof packer 3.3 would then proceedupon rupture of se'al'5'6 'and the test proceed in the same manner asabove described. To terminate the test it would merely be necessary toraise the drill pipe suiciently to unseat `the mechanical packer afterwhich Vthe inflatable packer-l33 would deate in the same manner asalready explained.

SIt is to beu'nderstodthat the invention is to be limited only by"the'fo'llowingfclaims, and not by the exact descriptioncontained in theforegoing specification, which has 'been presented merely by way ofexample and not of limitation.

"What is claimed is:

1. A'formation tester assembly for sampling uids from 'strataencountered in a well bore which comprises an 'elongatedrsupport memberattachable to the lower @11d of a drill pipe and having a central borecommunicating with'the interior of the drill pipe, an inatable elasticpabke'r attached to said support member, said packer having at le'a'stone test port in a side wall thereof, a mechanically expansible packersupported by the support member above vthe said inflatable `elasticpacker, means `for expanding said mechanically `expansible packer, -a.passageway within said assembly terminating atV its lower end withinsaid inflatable packerand at its upper end .in ag-.portfopeningexteriorly of saidy assembly abovensaid mechanical packer, saidpassageway lacking communication -with kthe central bore of the supportmemberfa conduitv connecting the test port of the inflatablee'lastic1packer with the central bore of the said support member belowsaid inflatable packer, and a pressure relief valve in said pressurerelief conduit.

3. A formation tester `assembly for sampling fluids from strataencountered in a well bore which comprises an elongated support memberattachable to the lower end of a drill pipe and having a central borecommunieating with the interior of the drill pipe, a rigid sleeveslidably arranged on the exterior of said support member, a iirstflexible packer member surrounding said support member adjacent saidsleeve, means fastening one end of said packer member to said supportmember, means fastening the other `end of said packer member to saidsleeve whereby on longitudinal motion of said sleeve relative to saidsupport member said packer member will expand outwardly, an inatableelastic packer fastened to said support member below said first packermember, said intlatable elastic packer having at least one test port ina sidewall thereof, a passageway within said support member terminatingat its lower end within said inflatable packer and at its upper end in aport opening exteriorly of said support member above said rst packermember, said passageway lacking communication with the central bore ofthesupport member, a conduit connecting the last named port of theinflatable elastic packer with the central bore of the support member, acheck valve in said last named conduit, and a frangible seal within anupper section of said central bore above said last named conduit.

4. A formation tester assembly for sampling lluids from strataencountered in a well bore which comprises an elongated support memberattachable to the lower end of a drill pipe and having a central borecommunicating with the interior of the drill pipe, a portion of saidsupport member being of enlarged cross-sectiona1 thickness, a rigidsleeve slidably arranged on the ex- 05 terior of said support member andenclosing and slidably engaging said enlarged portion thereof, saidsleeve being of enlarged bore in its mid-portion whereby` to alsoslidably contact said support member above and below said enlargedportion and to deiine with said enlarged portion an upper annularchamber and a lower annular ber below said rst packer member, saidinflatable elastic packer having at least one test port in a side wallthereof, a passageway within said support member terminating at itslower end within said inflatable packer and at its upper end in a portopening exterior of said support member above said rst packer member,said passageway lacking communication with the central bore of thesupport member, a conduit connecting the test port of the inflatableelastic packer with the central bore of the support member, a checkvalve in said last named conduit, and a frangble seal Within an uppersection of said central bore above said last named conduit.

5. Formation tester assembly as dei-ined by claim 4 including a springwithin one of said chambers exerting a bias on said sleeve in adirection resisting expansion of said rst named packer member.

References Cited in the le of this patent UNITED STATES PATENTS2,600,173 Sewell et al. June 10, 1952

1. A FORMATION TESTER ASSEMBLY FOR SAMPLING FLUIDS FROM STRATAENCOUNTERED IN A WELL BORE WHICH COMPRISES AN ELONGATED SUPPORT MEMBERATTACHABLE TO THE LOWER END OF A DRILL PIPE AND HAVING A CENTRAL BORECOMMUNICATPACKER ATTACHED TO SAID SUPPORT MEMBER, SAID PACKER HAVING ATLEAST ONE TEST PORT IN A SIDE WALL THEREOF, A MECHANICALLY EXPANSIBLEPACKER SUPPORTED BY THE SUPPORT MEMBER ABOVE THE SAID INFLATABLE ELASTICPACKER, MEANS FOR EXPANDING SAID MECHANICALLY EXPANSIBLE PACKER, APASSAGEWAY WITHIN SAID ASSEMBLY TERMINATING AT ITS LOWER END WITHIN SAIDINFLATABLE PACKER AND AT ITS UPPER END IN A PORT OPENING EXTERIORLY OFSAID ASSEMBLY ABOVE SAID MECHANICAL PACKER, SAID PASSAGEWAY LACKINGCOMMUNICATION WITH THE CENTRAL BORE OF THE SUPPORT MEMBER, A CONDUITCONNECTING THE TEST PORT OF THE INFLATABLE ELASTIC PACKER WITH THECENTRAL BORE OF THE SUPPORT MEMBER, A CHECK VALVE WITHIN SAID LAST NAMEDCONDUIT AND A FRANGIBLE SEAL WITHIN AN UPPER SECTION OF SAID CENTRALBORE ABOVE SAID LAST NAMED CONDUIT.